It depends. My daughter's pc is wireless and so is my laptop. However, my pc is not. The two pcs are all on the same network though even though one is wireless and one is wired. The laptop is on its own. All 3 use the same broadband connection to get to the internet. You have to configure two separate networks or subnets or use hardware to accomplish it. Not difficult to do though. Is the wireless and wired internal connections on the same router? If so, does that router allow for you to segregate them? I have a PIX 501 to do that for my laptop.

Look here for some solutions (I like a couple of them):

http://www.dslreports.com/forum/r19273852-Two-separate-networks-sharing-one-internet-connection

(You will have to create a login/password)

>>Mike,
>>>>You might consider locking down the machines that your daughters use.
>>>>
>>>>Naw, the Mac wasn't infected because viruses aren't usually cross-platform. If Macs were as prevalent as Windows machines, you would be hearing the same thing about them.
>>>
>>>They are locked down now and will remain that way until I get the two main computers straightened out. Then the plan is to back up what needs to be saved (downloaded music and pictures from their digital cameras mostly) and reformat both drives. What fun....
>>
>>I am mostly with the other Mike on "safety" of other platforms: the number of reachable targets is a large factor of the risk. While OSX fared better the XP, Leopard seems to have some trouble programmed for it. And if the number of targets is juicy someone will make a stronger effort and find a leak even in a more robust system.
>>
>>Currently I employ very draconian safety: sneaker net only for the kid's machines (usually something gets copied to those machines) and Internet only with a grown up watching and on a specific net-connected machine running knoppix. But that will change in the next years - so I am thinking of splitting off at least one secure subnet and/or employing virtual linux machines for browsing. Would be interested in your final layout and reasoning (and the ways to cope others have taken in similar position: Tracy, Al, Dragan, Jos - anybody else ?)
>>
>>Sometimes I loath the thought of things to come - Silverlight and the other attempts at Web3.0 will open the door for cross OS virus infection wider.
>>
>
>A thought that has crossed my mind is to remove the girls' two PCs from the home network completely. They could still get to the internet via the wireless network but would have no connection to other computers in the house. At least I think not?